"That 'silent killer' terminology is really unfair because the vast majority of women with ovarian cancer have had symptoms," Schink, chief of the division of gynecologic oncology at Cancer Treatment Centers of America, told INSIDER. "And many of those women have complained to somebody about their symptoms and people didn't listen or they weren't heard."

The problem, he explained, is that the common symptoms are non-specific, meaning doctors or patients often attribute them to other problems.

That's why it's important for people with ovaries — especially those with risk factors for ovarian cancer— to learn and stay alert for warning signs of the disease.

Here are potential symptoms to look out for — and when to see a doctor if you notice them.

The most common signs can seem non-specific

Needing to pee more often than usual is one of the more common ovarian cancer symptoms. Sara D. Davis/Getty Images

The most common ovarian cancer symptoms are an increase in belly size, pain, urinary changes, and feeling full quickly, according to the American Cancer Society (ACS).

"One of the most important [symptoms] is an increase in abdominal size that is happening quickly," Schink said. "Not like, 'OK, in the last 10 years I gained three inches.' It's like, 'I gained three inches this month.'" Some people also describe bloating as a symptom, he added.

Urinary frequency (having to pee more often than normal) or urgency (always feeling like you need to pee) can also signal the disease.

And finally, feeling very full after eating only a small amount of food — also called early satiety — can be a symptom, though Schink said this is "often a sign of fairly advanced ovarian cancer."

It's easy to see why Schink described these common symptoms as non-specific. They can all be caused by other, non-cancerous conditions. In fact, it's more likely that they're caused by non-cancerous conditions, according to the ACS.

Other possible signs include fatigue, constipation, and changes in your period

Fatigue may be a sign of ovarian cancer. REUTERS/Kevin Coombs

The ACS also lists fatigue, constipation, upset stomach, back pain, and pain during sex other potential symptoms of ovarian cancer.

It's also possible ovarian cancer could cause changes in periods. But Schink said it's not common sign because the majority of people who get ovarian cancer are peri- or post-menopausal, and have already stopped menstruating regularly. Even in pre-menopausal women, ovarian cancer may not stop periods, he added.

"The ovaries are a remarkable organ and in some women, they keep cycling even if one of them is really filled with cancer," Schink said.

Ovarian cancer symptoms are both new and persistent

Schink said true ovarian cancer symptoms have two key characteristics: They're new and they don't go away.

"I see patients all the time who have 12 hours of abdominal pain [say], 'Is this ovarian cancer?' And my comment to them is cancer symptoms generally come and while you wish they would go away, they don't. And that's the difference."

It's likely that ovarian cancer will cause more than one symptom, too. Schink said earlier research on ovarian cancer symptoms found that most patients had two or more signs of the disease.

"It wasn't just one thing suddenly wrong," Schink said. "You've got two or more symptoms of these rather nonspecific symptoms, but they're new to you, they don't go away, and they persist over the course of several weeks. That's kind of the key."

"People need to be aware that new treatments are emerging rapidly and survival continues to improve," he said. "Every year it gets better and we have new treatment options ... It's not a death sentence. It is becoming a more and more manageable cancer."